The invention relates to an arrangement for absorbing the sound emanating from a motor/pump unit, having a sound-deadening cover for the motor/pump unit.
An arrangement of this kind is known from U.S. Pat. No. 5,354,182. The motor/pump unit is surrounded by a sound-deadening cover. The motor/pump unit and the sound-deadening cover are held against one another. Angle pieces are screwed to the housing of the motor, being used to fix the motor/pump unit to an underlying support structure. Although an arrangement of this kind absorbs the airborne noise emitted by the motor/pump unit, the structureborne noise emanating from the motor/pump unit is transmitted to the cover and radiated to the outside. The cover, which deadens the airborne noise, acts like the diaphragm of a loudspeaker. This means that the larger the surface of the cover, the more sound is radiated.
The object on which the invention is based is to provide an arrangement of the type stated at the outset that not only absorbs airborne noise but also absorbs structureborne noise.
By the invention since the motor/pump unit and the sound-deadening hood do not touch one another in the operating condition, the structureborne noise of the motor/pump unit is not transmitted to the sound-deadening hood. On the other hand, however, since the motor/pump unit and the sound-deadening hood are supported on one another during transportation, they can be transported jointly in a simple manner.
Advantageous developments of the invention are provided. The catches for the joint transportation of the motor/pump unit and the sound-deadening hood are advantageously constructed in such a way that the motor/pump unit is held against the sound-deadening hood or that the sound-deadening hood is held against the motor/pump unit during transportation. If the catches are constructed in such a way that they engage in one another in a self-centering manner during the raising operation, the motor/pump unit and the sound-deadening hood cannot slip relative to one another during transportation. It is advantageous to provide one catch with a frustoconical outer surface and the other catch with a corresponding frustoconical inner surface. As an additional safeguard against vibration, a screwed joint is provided, which is passed through the catches. If the screwed joint is provided with transportation lugs at the head end, points of engagement for lifting gear are obtained in a simple manner.